Probably around $150 the light was the expensive part.
$70 for a light T5 Ho 4' lights 4 Total
$15 for a pump
$5 for the air stones
$20 for PH down and 1 Part nutrient solution
$5 for PH litmus paper
$15 for the plastic tray from Ikea
$10 for the sheet of 2" foam, 1" would have worked better
$10 for a 50 pack of grow plugs
The light stand I made out of left over Al extrusion from the 3D printer project I never finished.
As of yesterday that's only $75 per lettuce not including energy costs (figure heat in the winter doeskin count).
elizabeth Buttercrunch Lettuce. Need a verity that doesn't grow very tall and can tolerate warm weather w/o being bitter.